Take a look at the MOmarsh Invisilab. I have one and it's great. There is plenty of room for my lab to turn around when the back is closed up, and on hot days the back can be opened to let air through. The bottom is a mesh so water drains, and more ventilation. This is my first season with it but have used it in wheat fields, and water. The legs fold out under it and extend with individual adjustments.